Insect repellents

Abstract

Use of an N-substituted p-menthane carboxamide as an active ingredient in an insect repellent composition, which has little or no odour and which is substantially non-toxic for human, pet and livestock.

1 . Use as an insect repellent of a compound of the formula  
     
       
         
         
             
             
         
       
     
     wherein, 
 R 1  and R 2  are independently selected from the group consisting of H; an aliphatic residue having 1 to 20 carbon atoms, or a cycloaliphatic residue having 5 to 14 carbon atoms, or an aliphatic or cycloaliphatic residue aforementioned containing one or more hetero-atoms selected from O, N or S; an aryl or heteroaryl group having from 6 to 14 carbon atoms and wherein hetero-atoms are selected from O, N or S; or any of the afore-mentioned groups substituted with a group selected from, C 1-4  alkyl, C 1-4  alkoxy, C 2-4  alkenyl, aryl or heteroaryl as defined above, aryloxy, amino-, amido-, ester, keto-, hydroxyl, and halogen, or  
 R 1  and R 2  together with the nitrogen atom to which they are attached form a 5- or 6-membered ring that may optionally contain additional hetero-atoms selected from O, N or S.  
 
   
   
       2 . Use according to  claim 1  wherein the compound is selected from the group consisting of 
 Methyl-carbamic acid (−)-menthyl ester;    Ethyl-carbamic acid (−)-menthyl ester;    Butyl-carbamic acid (−)-menthyl ester;    Isobutyl-carbamic acid (−)-menthyl ester;    Diethyl-carbamic acid (−)-menthyl ester;    Pyrrolidine-1-carboxylic acid (−)-menthyl ester;    Piperidine-1-carboxylic acid (−)-menthyl ester;    Morpholine-4-carboxylic acid (−)-menthyl ester;    Phenyl-carbamic acid (−)-menthyl ester; and    3-[(−)-menthoxy-carbonylamino]-propionic acid ester.    
   
   
       3 . A compound selected from the group consisting of n-butyl-carbamic acid (−)-menthyl ester; iso-butyl-carbamic acid (−)-menthyl ester; diethyl-carbamic acid (−)-menthyl ester; morpholine-4-carboxylic acid (−)-menthyl ester; and 3-[(−)-menthoxy-carbonylamino]-propionic acid ester.  
   
   
       4 . A composition comprising a compound according to  claim 1  as defined in any of the preceding claims in an insect-repellent amount.  
   
   
       5 . A composition according to  claim 4  comprising at least one additional insect repellent.  
   
   
       6 . A composition according to  claim 4  comprising additionally at least one insecticide.  
   
   
       7 . A composition according to  claim 4  comprising additionally at least one fragrance ingredient.  
   
   
       8 . A method of repelling insects by applying to a substrate a preparation comprising at least one compound of the formula  
     
       
         
         
             
             
         
       
     
     wherein, 
 R 1  and R 2  are independently selected from the group consisting of H; an aliphatic residue having 1 to 20 carbon atoms, or a cycloaliphatic residue having 5 to 14 carbon atoms, or an aliphatic or cycloaliphatic residue aforementioned containing one or more hetero-atoms selected from O, N or S; an aryl or heteroaryl group having from 6 to 14 carbon atoms and wherein hetero-atoms are selected from O, N or S; or any of the afore-mentioned groups substituted with a group selected from, C 1-4  alkyl, C 1-4  alkoxy, C 2-4  alkenyl, aryl or heteroaryl as defined above, aryloxy, amino-, amido-, ester, keto-, hydroxyl, and halogen, or  
 R 1  and R 2  together with the nitrogen atom to which they are attached form a 5- or 6-membered ring that may optionally contain additional hetero-atoms selected from O, N or S.